Case for an electronic device and manufacturing methods formaking a case

ABSTRACT

An accessory unit includes a front flap and a rear cover. The rear cover includes a recessed portion that defines a chamber and a lip that extends about an opening of the chamber. The chamber is configured to receive a consumer electronic device, and the lip is configured to hold the consumer electronic device therein. The rear cover can include a shell formed from glass fiber reinforced plastics and a lip formed from a thermoplastic. The front flap may include segments formed from panels with folding regions therebetween, which allow the front flap to fold. Further, an end region of the front flap hingedly couples the front flap to the rear cover, such that the front flap may be moved between open and closed configurations. Methods of manufacturing the accessory unit are also disclosed.

FIELD

The described embodiments relate generally to an accessory of anelectronic device. In particular, the present embodiments relate tofeatures of the accessory unit and manufacturing methods for making theaccessory unit.

BACKGROUND

As advancements have been made in the field of consumer electronicdevices, development of associated accessory units has also occurred. Inthis regard, some accessory units such as cases are designed to protectconsumer electronic devices. Other accessory units are configured toprovide consumer electronic devices with increased functionality.

While existing accessory units may function suitably for their intendedpurposes, further advancements may be desirable. For example, increasedfunctionality or protection for the associated consumer electronicdevices may be desirable.

Also, as advancements are made in the field of consumer electronicdevices, development of associated accessory units also occurs. In thisregard, some accessory units such as cases are designed to protectconsumer electronic devices. Other accessory units are configured toprovide consumer electronic devices with increased functionality. Whileexisting accessory units may function suitably for their intendedpurposes, further advancements may be desirable.

SUMMARY

In one aspect, an accessory unit is described. The accessory unit mayinclude a front flap which includes several segments, an inner layer andan outer layer disposed on either side of the several segments. In someembodiments, the inner and outer layers allow the front flap to fold inregions between the several segments. The accessory unit may alsoinclude an end region. The accessory unit may also include a rear covercoupled to the front flap. The rear cover may include a shell forming arecessed region. In some embodiments, the inner layer and the outerlayer bonded on either side of the shell. The rear cover may alsoinclude a lip mechanically coupled along a periphery of the shell,wherein the lip is formed from a material more rigid than the shell andis configured to retain an electronic device within the recessed regionof the shell. In some embodiments, the end region of the front flaphingedly couples the front flap to the rear cover and the front flap isconfigurable between a closed configuration in which the front flap atleast partially covers the opening to the recessed region and an openconfiguration in which the opening to the recessed region is at leastpartially uncovered.

In another aspect, a method for forming a rear cover of an accessoryunit is described. The method may include shaping a recessed cavity froma composite material. The method may also include molding a lip along aperiphery of the recessed cavity, wherein the lip is formed from amaterial capable of co-curing with a resin used in the recessed cavity.The method may also include placing a unidirectional fiber within thelip, wherein the unidirectional fiber extends around a periphery of thelip.

In another aspect, a method for forming a button assembly on anaccessory unit is described. In some embodiments, the accessory unitincludes a structural shell, an inner cosmetic layer, and an outercosmetic layer. The method may include creating a chamfered opening inthe structural shell. In some embodiments, the chamfered opening isaligned with a button on an electronic device configured to rest withinthe accessory unit. The method may further include positioning a rigidfiller within the chamfered opening. In some embodiments, the rigidfiller has a chamfered edge corresponding to the chamfered opening inthe structural shell. The method may further include bonding the innercosmetic layer and outer cosmetic layer on either side of the structuralshell, wherein no adhesive is allowed to contact the rigid filler. Insome embodiments, the rigid filler is configured to transfer a forceexerted on the outer layer to a button disposed on the electronicdevice.

In another aspect, a button assembly for depressing a button on anelectronic device through an accessory having a structural shell, aninner cosmetic layer bonded to the structural shell, an outer cosmeticlayer bonded to the structural shell is described. The button assemblymay include an opening in the structural shell. The button assembly mayalso include a region of reduced thickness in the structural shellsurrounding the opening in the structural shell. The button assembly mayalso include an outer button over-molded onto the region of reducedthickness in the structural shell and protruding through the opening inthe shell. In some embodiments, the outer button is disposed between theinner cosmetic layer and the outer cosmetic layer. In some embodiments,the outer button is configured to transfer a forced exerted on the outercosmetic layer to a button disposed on the electronic device.

In another aspect, a case for a portable electronic device having ahousing and a display assembly carried by the housing is described. Thecase may include a recessed portion and a lip portion. The recessedportion may include a side wall. The lip portion may be integrallyformed with the recessed portion. The recessed portion and the lipportion may cooperate to define a chamber. The lip portion may furtherinclude a resilient material and be configured to retain the portableelectronic device within the chamber. The lip portion may furtherinclude an edge having a shape that defines an opening suitable forreceiving the portable electronic device. While receiving of theportable electronic device into the chamber, the edge may directlyengage the housing. The sidewall and the lip portion may cooperate toprovide an affirmative feedback indicating that the portable electronicdevice is fully secured within the chamber.

In another aspect, a method of forming a rear cover configured toreceive an electronic device is described. The method may includeapplying an adhesive to an inner portion of a shell and an outer portionof the shell. The shell may include a lip portion, and the shell may beconfigured to receive the electronic device. The method further includesapplying a first layer to a central portion disposed on the innerportion of the shell. The first layer may be configured to engage theinner portion and the lip portion. The first layer may also include anouter peripheral region. The method further includes expanding the innerlayer toward an inner surface of the shell. The inner surface extendsaround a perimeter of the shell. The method may further include applyinga second layer to the outer portion of the shell. The second layer mayinclude an outer peripheral region, and may be configured to engage thelip portion and the outer portion. The outer peripheral region of thesecond layer may be configured to engage the outer peripheral region ofthe inner portion. The method may further comprise curing the adhesive.

In another aspect, a method of forming a front cover for an electronicdevice is described. The may include providing a fabric layer having atop surface and a bottom surface opposite the top surface. The fabriclayer may also include a first thickness measuring from a verticaldistance between the top surface and the bottom surface. The method mayfurther include positioning the fabric layer such that the fabric layerincludes a first elevated portion and a second elevated portion. A non-elevated portion of the fabric layer may extend between the firstelevated portion and the second elevated portion. The method may furtherinclude applying a first cut on the top surface at the first elevatedportion thereby forming a first cut portion. The method may furtherinclude removing the first elevated portion.

Other systems, methods, features and advantages of the embodiments willbe, or will become, apparent to one of ordinary skill in the art uponexamination of the following figures and detailed description. It isintended that all such additional systems, methods, features andadvantages be included within this description and this summary, bewithin the scope of the embodiments, and be protected by the followingclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will be readily understood by the following detaileddescription in conjunction with the accompanying drawings, wherein likereference numerals designate like structural elements, and in which:

FIG. 1A shows a perspective view of an accessory unit comprising a frontflap and a rear cover with the front flap in an open configuration;

FIG. 1B shows a cross sectional view of the accessory unit shown in FIG.1A in the open configuration;

FIG. 2A illustrates a perspective view of the accessory unit of FIG. 1Awith the front flap in a closed configuration;

FIG. 2B illustrates a cross sectional view of the accessory unit of FIG.2A with the front flap in a closed configuration;

FIG. 3 illustrates an exploded perspective view of the accessory unit ofFIG. 1A in the open configuration;

FIG. 4A shows a cross-sectional view of the shell and lip of the rearcover;

FIG. 4B shows a cross-sectional view of the shell with a separate lipcomponent;

FIG. 4C shows a cross-sectional view of the shell and lip of the rearcover with an added fiber reinforcement in the lip portion;

FIG. 5 shows an apparatus for placing a fiber in the lip portion duringthe curing process;

FIG. 6 shows a flow chart depicting a process for molding a lip onto ashell;

FIG. 7 shows a flow chart depicting a process for molding a lip onto ashell with a fiber held within the lip;

FIG. 8A shows a perspective view of a shell with several blind holes foropenings;

FIG. 8B shows a cross-sectional of the shell of FIG. 8A;

FIG. 8C shows a cross-sectional of the shell of FIG. 8A;

FIG. 9 shows a flow chart depicting a process for creating a holethrough an accessory unit while displaying a minimal amount of shell;

FIG. 10A illustrates a process for trimming an excess amount of coveringmaterial from an accessory unit;

FIG. 10B shows a cross-sectional view of a shell with inner and outerlayers bonded and trimmed;

FIG. 11A illustrates a process for curing an adhesive using a plug;

FIG. 11B illustrates a process for curing an adhesive using a rollingheater;

FIG. 11C illustrates a process for curing an adhesive using a deformableplug;

FIG. 12A shows a cross-sectional view of a hinge mechanism utilizing tworigid stiffeners;

FIG. 12B shows a cross-sectional view of a hinge mechanism utilizingmagnets;

FIG. 13A shows a cross-sectional view of a button assembly using a rigidfiller to depress a button;

FIG. 13B shows a cross-sectional view of a button assembly using anover-molded outer button to depress a button;

FIG. 13C shows a flow chart depicting a process for creating a buttonassembly;

FIG. 13D shows a flow chart depicting a process for creating a buttonassembly;

FIG. 14 illustrates a cross sectional view of the accessory unit shownin FIG. 1A in the open configuration;

FIG. 15 illustrates a perspective view of the accessory unit of FIG. 14with the front flap in a closed configuration;

FIG. 16 illustrates a cross sectional view of the accessory unit of FIG.15 with the front flap in a closed configuration;

FIGS. 17A-17C illustrate cross-sectional side views various embodimentsof shells;

FIGS. 17D-17G illustrate cross-sectional side views schematicallyshowing a method for forming a rear cover portion of an accessory unit;

FIGS. 18A-19D illustrate a side cross sectional views showing variousfeatures relating to sidewalls of an accessory unit;

FIGS. 19A-19E illustrate cross sectional views showing a method forskiving a piece of fabric;

FIG. 20 illustrates a block diagram representing a method for assemblingan accessory unit;

FIGS. 21A-21D illustrate various embodiments of hybrid shells suitablefor use as a shell within an accessory unit;

FIG. 22 is a block diagram of an arrangement of functional modulesutilized by a portable media device; and

FIG. 23 is a block diagram of an electronic device suitable for use withthe described embodiments.

Those skilled in the art will appreciate and understand that, accordingto common practice, various features of the drawings discussed below arenot necessarily drawn to scale, and that dimensions of various featuresand elements of the drawings may be expanded or reduced to more clearlyillustrate the embodiments of the present invention described herein.

DETAILED DESCRIPTION

Reference will now be made in detail to representative embodimentsillustrated in the accompanying drawings. It should be understood thatthe following descriptions are not intended to limit the embodiments toone preferred embodiment. To the contrary, it is intended to coveralternatives, modifications, and equivalents as can be included withinthe spirit and scope of the described embodiments as defined by theappended claims.

In the following detailed description, references are made to theaccompanying drawings, which form a part of the description and in whichare shown, by way of illustration, specific embodiments in accordancewith the described embodiments. Although these embodiments are describedin sufficient detail to enable one skilled in the art to practice thedescribed embodiments, it is understood that these examples are notlimiting such that other embodiments may be used, and changes may bemade without departing from the spirit and scope of the describedembodiments.

Accessory units are commonly used in conjunction with consumerelectronic devices. Some accessory units are configured to protectconsumer electronic devices. For example, cases may be employed topartially or fully surround a consumer electronic device such that theconsumer electronic device is protected from damage. By way of furtherexample, stands for consumer electronic devices may be configured toprop up the consumer electronic devices such that they may beconveniently positioned for interaction therewith. Another accessoryunit can take the form of a foldable cover that can be detachablyconnected to, for example, a tablet computer. Some accessory units canbe configured to move between multiple configurations, including oneconfiguration in which the accessory unit functions as a cover andanother configuration in which the accessory unit functions as a stand.

These and other embodiments are discussed below with reference to FIGS.1-XX. However, those skilled in the art will readily appreciate that thedetailed description given herein with respect to these figures is forexplanatory purposes only and should not be construed as limiting. Forthe remainder of this discussion, an accessory unit suitable for usewith an electronic device will be described. In particular, forsimplicity and clarity, for the remainder of this discussion, theelectronic device takes the form of a handheld electronic device such asa tablet computer.

In this regard, FIGS. 1A and 1B illustrate an embodiment of an accessoryunit 100 according to the present disclosure. As illustrated, theaccessory unit 100 can comprise a front flap 200 and a rear cover 300.The front flap 200 can include a plurality of segments 202 and a foldingregion 204 positioned between each of the segments. The folding regions204 can be configured to allow the segments 202 to fold with respect toeach other. The front flap 200 can also include an end region 206. Theend region 206 can hingedly couple the front flap 200 to the rear cover300.

In a specific embodiment, each of segments 202 can include one or moreinserts disposed therein. By way of example, segments 202 can include apocket region where the inserts are placed, or alternatively the insertscan be embedded within the segments (e.g., via insert molding). Ifpockets are used, the pocket region can have a size and shape toaccommodate corresponding inserts. The inserts can have various shapesbut are most typically shaped to conform to the overall look of frontflap 200 (e.g., rectangular). The inserts can be used to providestructural support for front flap 200. That is, the inserts can providestiffness to the cover assembly. In some cases, the inserts can bereferred to as stiffeners. The inserts can be formed of rigid orsemi-rigid material adding resiliency to front flap 200. Examples ofmaterials that can be used include plastics, fiber glass, carbon fibercomposites, metals, and the like. Some of the inserts can be formed ofresilient material such as plastic but also arranged to accommodateother components such as magnetic elements described below. Some of themagnetic elements can take the form of magnets, at least one of whichcan interact with a magnetic sensor disposed within an electronic deviceassociated with accessory unit 100. In some embodiments, some of themagnets can also be arranged to form a magnetic attraction with anattractable magnetic element disposed within at least one insert. In oneembodiment, the attractable magnetic elements can be formed of steel, orother ferromagnetic material, and take the shape of a thin sheetincorporated within an insert.

Front flap 200 can be relatively stiff except along folding regions 204that are thinner and do not include the inserts (e.g., allows folding)making front flap 200 more robust and easier to handle. In addition, thespacing between folding regions 204 can be configured to allow segments202 to be arranged into a triangular support structure. This triangularsupport structure can support the electronic device at an angle thatallows a user to operate the device without having to support the devicewith hands. In one embodiment, the triangular support structure can beformed by placing one or more magnets in segments 202 configured to holdthe segments together in a desired shape. In another embodiment,friction can be sufficient to maintain the triangular structure withoutthe need for magnets.

The rear cover 300 can include a recessed portion 302 and lip 304. Therecessed portion 302 can include a plurality of sidewalls 306 a-d(collectively, “306”) and a bottom wall 308 that define a chamber 310.The recessed portion 302 can include one or more apertures 312 a-e(collectively, “312”) and/or one or more embossed portions 314 a-b(collectively, “314”). The lip 304 can be coupled to the recessedportion 302 and extend about an opening 316 of the chamber 310. As willbe described in further detail below, the recessed portion 302 of therear cover 300 may be formed from a composite material. Additionally,the lip 304 can be formed from a material that is more rigid than thecomposite material of the recessed portion 302. In this regard, the lip304 of the rear cover 300 can be configured to retain a consumerelectronic device in the chamber 310, as discussed in detail below.Also, apertures 312 may be employed to provide access to variouscomponents of the consumer electronic device such as audio, power, anddata ports. Further, one of the apertures 312 c may be configured toalign with a camera lens of a consumer electronic device (not shown). Inthis regard, the aperture 312 c may be oversized relative to the size ofthe camera lens in order to ensure that the camera lens is not blockedeven when the consumer electronic device is not perfectly aligned in therear cover 300. In one embodiment, apertures 312 can be punched into athermoplastic shell that provides structure to accessory unit 100. Aliquid crystal polymer fiber can be added around apertures 312 toreinforce apertures 312. In one specific embodiment, a 70 micron thicklayer of liquid crystal polymer fiber can be utilized to providedurability to apertures 312. One specific type of liquid crystal polymerfiber that can be utilized for such a purpose is VECTRAN® fiber.

The lip portion 304, including lip portions 304 a-d as shown in FIG. 1A,can be integrally formed with the recessed portion 302 and extend aboutan opening 316 of the chamber 310. It should be noted that in alternateembodiments lip portion 304 can be a separate rigid frame member incontact with recessed portion 302. As will be described in furtherdetail below, the recessed portion 302 of the rear cover 300 may beformed from a flexible material. Additionally, the lip portion 304 maybe formed from a material that is more rigid than the flexible materialof the recessed portion 302. In this regard, the lip portion 304 of therear cover 300 may be configured to retain a consumer electronic devicein the chamber 310, as discussed in detail below. In some embodiments,the rigidness of lip portion 304 can be due substantially to a thicknessof lip portion 304 with respect to recessed portion 302.

The front flap 200 may be configurable between an open configuration(see, e.g., FIG. 1A) and a closed configuration (see, e.g., FIG. 2A). Inthe open configuration, the front flap 200 is displaced relative to therear cover 300 such that the opening 316 to the chamber 310 is at leastpartially uncovered. For example, FIG. 1A illustrates a fully openconfiguration in which the front flap 200 is out of contact with the lip304 and the front flap defines a substantially planar configuration. Inaddition, as was described above, the front flap 200 can also be placedin a triangular configuration when in the open position to form a standfor the electronic device.

As illustrated in FIG. 2A, the edges 210 of the front flap 200 cancontact the lip 304 when front flap 200 is in the closed configuration.Accordingly, the front flap 200 can define a substantially planarconfiguration when moved to the closed configuration. In this regard,the end segment 208 can be substantially coplanar with the othersegments 202 and the folding regions 204 of the front flap when thefront flap is in the folded configuration. However, a portion of the endregion 206 adjacent the end segment 208 can bend to enable end region206 to function as a hinge.

In some embodiments, as illustrated in FIG. 2A, the lip 304 can extendoutwardly beyond the edges 210 of the front flap 200. In this regard,the lip 304 can function to protect a consumer electronic devicereceived in chamber 310 in the rear cover 300 from damage to the edgesthereof when dropped or otherwise subjected to impact. However, in otherembodiments the edges 210 of the front flap 200 and the lip 304 canextend to the same dimensions, or the edges of the front flap can extendbeyond the lip 304.

The material(s) defining the accessory unit 100 may vary. In one exampleembodiment, the entire accessory unit 100 may be formed from a singlematerial. However, as noted above, in other embodiments it may bedesirable to form the accessory unit 100 from multiple materials to takeadvantage of differing material properties.

In this regard, FIG. 3 illustrates an exploded view of one embodiment ofthe accessory unit 100 in the open configuration. As illustrated, theaccessory unit 100 can include a single sheet of material that definesan inner layer 102 of the front flap 200 and the recessed portion 302 ofthe rear cover 300. Further, the accessory unit 100 can include a singlesheet of material that defines an outer layer 104 of the front flap 200and the recessed portion 302 of the rear cover 300. In this regard, therecessed portion 302 of the rear cover 300 and the front flap 200 can beat least partially integrally formed in one embodiment, providing apleasing, continuous appearance to the visible surfaces of accessoryunit 100. However, the rear cover 300 and the front flap 200 can beformed from separate materials in other embodiments.

The material(s) defining the inner layer 102 and the outer layer 104 canbe the same or different. In one embodiment, both the inner layer 102and the outer layer 104 can be formed from a microfiber material,leather-like material, or any other technically feasible material. Inanother embodiment the inner layer 102 can include a microfiber materialand the outer layer 104 can include poly urethane type materials such asPUK. In this regard, the inner layer 102 and the outer layer 104 caninclude materials configured to provide durability, provide flexibility,protect a consumer electronic device, and/or a pleasing aestheticappearance. In some embodiments the inner layer 102 can also beconfigured to passively clean the consumer electronic device, which maycome into contact with the inner layer while held therein.

In some embodiments, the accessory unit 100 can further include one ormore additional materials between the inner layer 102 and the outerlayer 104. For example, the accessory unit 100 can include one or morepanels 106. The panels 106, which may include fiberglass, steel, carbonfiber, plastic, or other relatively rigid materials in some embodiments,can be configured to define the structure of the segments 202 of thefront flap 200. In turn, the areas between the panels 106 can define thefolding regions 204 of the front flap 200, with the inner layer 102 andthe outer layer 104 providing the folding regions with flexibility.

The accessory unit 100 can further include one or more magnetic elementsin the front flap 200. In one embodiment, one or more magnetic elements108 can be configured to interact with an attachment feature of aconsumer electronic device received in rear cover 300. For example, themagnetic elements 108 can be magnetically attracted to the attachmentfeature of the consumer electronic device when the accessory unit 100 isin a closed configuration such that the front flap 200 is releasablyretained in this configuration. The front flap 200 can further include amagnetic element 110 configured to interact with a magneticallysensitive sensor configured to detect presence, absence, or a changefrom presence to absence or vice versa of the magnetic element. Forexample, the magnetically sensitive circuit can include a Hall Effectsensor.

As an example, the Hall Effect sensor can respond to the presence (orabsence) of a magnetic field by generating a signal. The signal can beused to alter an operating state of the electronic device. Accordingly,magnetic element 110 can be positioned on front flap 200 in a locationthat triggers the Hall Effect sensor to generate the signal when thecover is placed on or in proximity to a surface of the consumerelectronic device. The signal can indicate that the front flap 200 is ina predetermined position relative to the consumer electronic device thatcan result in a change in an operating state of the consumer electronicdevice. For example, with a portion of front flap 200 having magneticelement 110 in proximity to the Hall Effect sensor, the magnetic fieldfrom magnetic element 110 can cause the Hall Effect sensor to generate asignal. The signal can, in turn, be used to alter the operating state toone consistent with functioning of the consumer electronic device beingfully covered.

For example, in those situations where the consumer electronic deviceincludes a display, the functioning of the consumer electronic productcan be altered in such a way that the display is prevented fromdisplaying visual content. On the other hand, when the portion of frontflap 200 having magnetic element 110 is removed to the point where theHall Effect sensor no longer responds to the magnetic field of magneticelement 110, then the Hall Effect sensor can generate another signal.The other signal can result in the consumer electronic device enteringanother, different, operating state consistent with at least a portionof the display being uncovered and viewable. As with the example of theconsumer electronic product having a display, when the Hall Effectsensor no longer detects the magnetic field from magnetic element 110,then the functioning of the tablet computer can be altered such that thedisplay is enabled to present visual content.

The accessory unit 100 can further include one or more end panels 112between the inner layer 102 and the outer layer 104, which can beconfigured to define the structure of a portion of the end region 206 atthe end segment 208. The end panels 112 can include fiberglass, steel,carbon fiber, plastic, or other relatively rigid materials in someembodiments. Accordingly, the material(s) defining the inner layer 102and the outer layer 104 (e.g., microfiber, leather, or any othersuitable material) can include flexible materials that allow the frontflap 200 to flex at the folding regions 204 and at the end region 206,whereas the material(s) defining the panels 106 can provide rigidity andstiffness. In some embodiments, the front flap 200 can also include areinforcement bar 114. The reinforcement bar 114 can be configured toreinforce the outer edge 210 c of the front flap 200 and the cornersbetween the outer edge and the side edges 210 a and 210 b of the frontflap 200. Accordingly, the reinforcement bar 114 can be formed from arelatively rigid material such as plastic, steel, carbon fiber,fiberglass, etc.

The accessory unit 100 can also include shell 118. Shell 118 can bepositioned between inner layer 102 and outer layer 104 in the area ofrear cover 300, and can provide stiffness to rear cover 300. Shell 118can be formed from a variety of materials, including thermoplastics,composites, and the like. In the described embodiments, shell 118 can beformed primarily of Glass Fiber Reinforced Plastic (GFRP) that is alsoreferred to as more simply fiberglass. GFRP is a fiber reinforcedpolymer made of a plastic matrix reinforced by fine fibers of glass. Itshould be noted that the plastic matrix used to form many GFRPstructures can be a thermosetting plastic (most often epoxy, polyesteror vinyl ester) or thermoplastic. Moreover, GFRP is a lightweight,extremely strong, and robust material and has bulk strength and weightproperties that compare favorably to metals and yet, unlike metals, isRF transparent. In this way, GFRP has properties that make it a goodcandidate for a structural element that is strong, resilient and yet isalso RF transparent. This combination is particularly desirable whenaccessory unit 100 is used in conjunction with consumer electronicproducts that use RF communication circuitry.

In addition, shell 118 can include a variety of openings configured toprovide access to various buttons, camera holes, speaker ports, etc. Insome embodiments, speaker cover 116 can be included between shell 118and inner layer 102 or outer layer 104, including perforations to allowsound to escape from speakers included in the electronic device. Shell118 can be attached to inner layer 102 and outer layer 104 using avariety of adhesives. In one embodiment, a heat activated adhesive canbe used to attach both inner layer 102 and outer layer 104 to shell 118.However, any technically feasible adhesive can be used to form areliable connection. Lip 304 can be provided around a periphery of shell118 to provide structural stiffness to rear cover 300 and an overhangfor retention of the electronic device. In some embodiments, lip 304 canbe integrated into shell 118. In other embodiments, lip 304 can beformed as a separate component and attached to shell 118 during anassembly process. More detail regarding lip 304 and the interfacebetween lip 304 and shell 118 are described below.

The front flap 200 can include inner and outer adhesive layers 120 and122 that bond the layers of material defining the front flap together.In particular, the outer adhesive layer 120 can bond the outer layer 104to the reinforcement bar 114 and the panels 106 and the end panel 108.Further, the inner adhesive layer 120 can bond the inner layer 102 tothe reinforcement bar 114, the panels 106, and the end panel 112.Accordingly, the adhesive layers 120 and 122 can laminate the layers andcomponents comprising the front flap 200 together.

In some embodiments the adhesive layers 120 and 122 can comprise athermoplastic adhesive, such as a thermoplastic urethane adhesive, or athermoplastic nylon adhesive. Such thermoplastic adhesives can act toform a structural element providing shape to inner layer 102 and outerlayer 104 which on their own would not hold a solid shape. In thisregard, thermoplastic adhesives can be melted in order to glue togethermultiple layers of material (e.g., inner layer 102 and outer layer 104).By varying the temperature at which the thermoplastic adhesives areheated, the pressure at which the operation takes place, the length oftime the thermoplastic adhesives are exposed to the heat, and thetemperature to which the thermoplastic adhesives are cooled afterheating, the rigidity of the structure defined thereby can becontrolled. For example, in one embodiment, as the thermoplasticadhesive melts the adhesive can seep into adjacent porous layers ofmaterial, forming a bonded structure. Longer periods of heating canresult in increased infusion into the material and can create a morerigid structure.

In some embodiments, the flexibility of front flap 200 can also becontrolled by locally thinning regions of inner layer 102 and outerlayer 104. This can be particularly important when inner and outerlayers 102 and 104 are formed from a relatively stiff material such asleather. In one embodiment, the local thickness of layers 102 and 104can be reduced by running an abrasion tool such as a horizontal sandingwheel along a non-visible surface of layers 102 and 104 in regions 204prior to assembly. In other embodiments, the same effect can be achievedusing a laser or splitting machine.

Furthermore, some embodiments of accessory unit 100 can include featuresconfigured to retain flexibility of the end region 206 of the front flap200. In the embodiment of the accessory unit 100 illustrated in FIG. 3,the inner and outer adhesive layers 120 and 122 of the front flap 200may not completely cover the end region 206. Rather, as illustrated, theinner and outer adhesive layers 120, 122 can include tab 122′ thatextends across the end region 206 proximate the side edges 210 a and 210b of the front flap 200. In particular, tab 122′ can be configured toextend across the end region 206 of the front flap 200 to the edge ofthe rear cover 300. Accordingly, in embodiments in which the front flap200 includes multiple layers of material, the layers of the material canbe bonded at first and second longitudinal ends 206 a and 206 b of theend region 206 and decoupled therebetween due to tab 122′ bonding thelongitudinal ends of the end region. By bonding only a portion of theend region 206, the inner layer 102 and the outer layer 104 may remainfree to pivot with respect to each other. Thus, the end region 206 canfunction as a hinge as previously described. Other embodiments of thehinge between front flap 200 and rear cover 300 are described below.

FIG. 4A shows a cross-sectional view of shell 118 and lip 304,demonstrating how lip 304 can retain electronic device 402 withinaccessory unit 100. The materials used for forming shell 119 and lip 304can be chosen to provide rear cover 300 with mechanical propertiessufficient to securely retain electronic device 402 within rear cover300, while at the same time retaining enough flexibility to allowelectronic device 402 to be inserted and removed numerous times withoutundue exertion by an end-user or potentially damaging accessory unit 100or electronic device 402. In order to insert and remove electronicdevice 402, both shell 118 and lip 304 can deflect outwards in direction404. In one embodiment, electronic device 402 can include chamfer 412around a periphery of an upper surface. When this is the case, the shapeof shell 118 and lip 304 can be configured to provide two points ofcontact at both edges of the chamfer. The result of this two pointengagement is a “snap” experience when electronic device 402 is fullyengaged within rear cover 300. This snap can provide an enhanced userexperience and assist in alerting the user that electronic device 402 isfully retained within rear cover 300.

In one embodiment, shell 118 and lip 304 can be formed from the samematerial. The material used can include thermoplastics, fiber reinforcedplastics, polymers, and the like. However, there can be severaldisadvantages to forming both shell 118 and lip 304 from the samematerial. First, it can be difficult to locate a material that possessesthe mechanical properties necessary to protect and hold in placeelectronic device 402 while simultaneously having the flexibility toallow electronic device 402 to be easily inserted and removed. Second,the undercut formed by lip 304 can complicate the molding process whenshell 118 and lip 304 are formed as a single part, necessitating the useof sliders or other moving parts in the mold.

The above mentioned difficulties can be removed by forming shell 118 andlip 304 from different materials. FIG. 4B shows an alternativeembodiment in which shell 118 and lip 304 are made from differentmaterials and joined during an assembly process. For example, shell 118can be formed from a glass-fiber reinforced plastic while lip 304 can beformed from a thermoplastic material. The combination of differentmaterials can provide a satisfactory combination of mechanical strengthand flexibility to both protect electronic device 402 and allow for easyinsertion and removal. In one embodiment, the resin used in shell 118can be closely matched to the thermoplastic used in lip 304, such thatboth resins can cure simultaneously and form a bond along surface 408.More detail regarding this process is shown in FIG. 6.

FIG. 4C shows yet another embodiment of shell 118 and lip 304. Similarto the embodiment shown in 4B, shell 118 and lip 304 can be formed fromseparate materials. For example, shell 118 can be formed from aglass-fiber reinforced plastic while lip 304 can be formed from athermoplastic. However, lip 304 can also include one or more strands offiber 410 along the length of lip 304. The added fibers can increase therigidity of lip 304. Fibers 410 can be selected from a number of fibersincluding Kevlar, glass fibers, carbon fibers, and the like. In oneembodiment, fiber 410 can be introduced in the assembly during thecuring process for shell 118 and lip 304, allowing all three componentsto cure simultaneously. In other embodiments, fiber 410 can be added toan outer surface of lip 304 after lip 304 has been cured. In this case,fiber 410 can be attached to lip 304 using adhesives, solder, or anyother technically feasible means. An apparatus for inserting fiber 410into lip 304 during the curing process is shown in FIG. 5 and a processfor including fiber 410 is described in FIG. 7.

FIG. 5 shows apparatus 500 for including fiber 410 in lip 304 during thecuring process. Shell 118 can placed in a mold and an over-mold forforming lip 304 can be placed over shell 118. Corner guides 502 can beplaced along interior corners of lip 304 and fiber 410 can be wrappedaround an outer surface of the corner guides 502. Pegs 506 and 508 canbe used to direct fiber 410 away from apparatus 500 and tighten fiber410 until it is taut. The combination of corner guides 502 and pegs 506and 508 can hold fiber 410 in place while lip 304 is cured. As a result,fiber 410 becomes an integral part of lip 304 and can greatly increasethe rigidity of lip 304.

FIG. 6 shows a flow chart depicting process 600 for simultaneouslycuring a shell and a lip for an accessory unit. In step 602, aglass-fiber reinforced composite can be molded into the shape of theshell. In other embodiments, the shell can be molded from othermaterials such as thermoplastics. The resin used in the molding processcan either be added at this time or be pre-impregnated in the fibers. Instill other embodiments, fibers other than glass can be used in thecomposite framework, including Kevlar, carbon fiber, and the like. Next,in step 604, the curing process for the shell can begin. This caninclude heat, time, UV-curing, or any other technically feasible meansof curing. While the curing process for the shell is still in progress,in step 606, the lip can be molded over the edge of the shell. The lipcan be formed using a resin or thermoplastic with properties similar tothe resin used in the shell. This can ensure that a strong bond isformed between the shell and lip. Finally, in step 608, the shell andlip can be allowed to cure together and form one part.

FIG. 7 shows a flow chart depicting process 700 for including one ormore strands of fiber in the lip of the rear cover. In step 702, aglass-fiber reinforced composite can be molded into the shape of theshell. In other embodiments, the shell can be molded from othermaterials such as thermoplastics. The resin used in the molding processcan either be added at this time or be pre-impregnated in the fibers.

In still other embodiments, fibers other than glass can be used in thecomposite framework, including Kevlar, carbon fiber, and the like. Next,in step 704, an over-mold for forming the lip can be positioned over theedge of the shell. Then, in step 706, one or more strands of fiber canbe passed through the mold for the lip and tightened. In someembodiments, an apparatus with corner guides and tightening pegs such asthe apparatus depicted in FIG. 5 can be used to align the fibersproperly within the mold. Next, in step 708, the lip material can beinjected into the lip mold. The lip material can include a resin orthermoplastic with properties similar to the resin used in the shell.Finally, in step 710, the shell, lip, and fiber strands can be allowedto cure together and form one unified part.

FIG. 8A shows shell assembly 800, demonstrating a method for creatingthrough holes in accessory unit 100 while minimizing the degree to whichthe shell is visible to the user. Accessory unit 100 can include avariety of through openings allowing the electronic device to be exposedto the outside environment in limited areas. These can include openingsfor cameras, headphone jacks, speakers, microphones and the like. Ifthese openings are created through inner layer 102, shell 118, and outerlayer 104, then a significant portion of shell 118 can be visible to theuser around an interior of the opening. Often times, shell 118 can be adifferent color than inner layer 102 and outer layer 104, resulting inan opening that is not aesthetically pleasing. FIGS. 8A-8C demonstratehow this discontinuity can be minimized or eliminated. Areas 802 canrepresent regions in which through holes are needed for a camera,headphone jack, or other type of opening. Shell 118 can be drilled ormachined to create a blind hole in these regions. For example, if thetotal thickness of shell 118 is approximately 0.4 mm, regions 802 can bemachined down to a thickness of 0.2 mm. It should be noted that thesenumbers are representative and any percentage of the thickness of shell110 can be removed during this process.

Referring to FIG. 8B, a cross-sectional view of region 802 is shownafter inner layer 102 and outer layer 104 have been affixed and thethrough hole has been cut. Inner layer 102 can follow the contour ofshell 118 as the thickness is reduced from the normal thickness to thatof the blind hole. As such, the visible portion of shell 118 isdecreased from distance d1 to distance d2. Often times, this reductioncan reduce the thickness of shell 118 to the point where it is notvisible to the human eye upon casual inspection of accessory unit 100.FIG. 8C shows another embodiment in which a through hole is used inplace of a blind hole in regions 802. In this case, inner layer 102 andouter layer 104 are bonded directly to each other in the areasurrounding the final through hole. This method can ensure that shell118 is completely invisible to the user, but offers less structuralsupport around the opening. For this reason, the technique shown in FIG.8B is preferable when used around openings in higher stress areas ofaccessory unit 100.

FIG. 9 shows a flow chart depicting process 900 for minimizing an amountof visible shell in an opening through an accessory unit. In step 902, ablind hole is drilled or machined in an area where an opening isdesired. The blind hole should be larger than the desired opening.Preferably, the blind hole should be placed on a non-visible side of theaccessory unit. However, the hole can be placed on either side if sodesired. The depth of the hole can be approximately half the thicknessof the shell or any other suitable depth. Next, in steps 904 and 906,the inner and outer layers are bonded on both surfaces of the shell.Finally, in step 908, the desired opening is cut through the innerlayer, shell, and outer layer at the center of the blind hole. Thereduced thickness of the shell around the periphery of the opening canmake the appearance of the opening more aesthetically pleasing to theuser.

FIGS. 10A and 10B show a cross-sectional view of accessory unit 100 asinner layer 102 and outer layer 104 are applied to shell 118 and lip304. In some embodiments, inner layer 102 and outer layer 104 can makeup one piece of material that wraps around the entirety of accessoryunit 100 and meets along one seam. Inner and outer layers 102 and 104can be formed from a variety of different fabrics and materials.Preferably, layers 102 and 104 can be formed low recovery or “high set”fabrics that tend to remain in a deformed state when they are stretchedto form around the contours of an object such as accessory unit 100. Inaddition, it can be preferable to use fabrics that bond well withadhesives. In some embodiments, a primer can be placed on either shell118 or inner and outer layers 102 and 104 to increase the stiction ofthe bond between the two.

Inner layer 102 and outer layer 104 can be bonded using any suitableadhesive. In one embodiment, thermoplastic adhesives can be used.However, the use of thermoplastic adhesives can be problematic with somematerials due to the high heat needed to cure thermoplastic adhesives.For example, the temperatures needed to cure a thermoplastic adhesivecan damage some forms of leather and polyurethanes. In anotherembodiment, thermosetting glues can be used in place of thermoplasticadhesives. Thermosetting glues can cure at temperatures as low as 80degrees F. and can therefore be more appropriate for use withtemperature sensitive materials. As is shown in FIG. 10A, an excessamount of material can be left after inner layer 102 and outer layer 104are bonded to shell 118 and lip 304. The excess material can be removedusing diecut 1002 to leave seamless finish 1004 shown in FIG. 10B. Inone embodiment, diecut 1002 can consist of a machined, single sidedblade with tolerances sufficient to ensure that a precise cut is made.However, any suitable method for cutting material can be used to trimexcess material from inner layer 102 and outer layer 104.

FIGS. 11A-11C demonstrate methods for curing thermosetting glue aroundan edge region of rear cover 300. One problem that can arise whenbonding inner layer 102 to shell 118 and lip 304 is maintainingsufficient pressure and heat underneath the overhang formed by lip 304while the adhesive is curing. FIG. 11A demonstrates one method ofsolving this problem using a heated plug 1102 during the curing process.Plug 1102 can have a shape similar to that of the electronic deviceaccessory unit 100 is designed to accommodate and be formed from athermally conductive material such as steel, metal, or brass. Thecombination of heat and pressure under lip 304 can allow inner layer 102to firmly adhere to shell 118 and lip 304.

FIG. 11B shows an alternative method of providing heat and pressureusing a rotating fixture 1104. Fixture 1104 has a shape configured toconform to the interior of shell 118 and lip 304. In addition, fixture1104 can rotate about axis 1106 and translate around a periphery ofshell 118, providing intermittent pressure and heat during the curingprocess. Finally, FIG. 11C demonstrates yet another method of creatingpressure under lip 304. Deformable material 1108 can be placed withinthe cavity formed by shell 118. Deformable material 1108 can be anymaterial capable of deforming in response to pressure such as silicon.Once in place, pressure can be applied along a top surface of deformablematerial 1108, causing the portion of deformable material 1108 withinshell 118 to expand outwards and fill any crevices. This outwardpressure can hold inner layer 102 in place against shell 118 and lip 304during the curing process.

As noted above, front flap 200 can be hingedly coupled to rear cover300. FIGS. 12A and 12B show various embodiments of means for forming anacceptable hinge mechanism. Inner layer 102 and outer layer 104 areformed from flexible materials and can span between front flap 200 andrear cover 300, providing means for front flap 200 to rotate betweenopen and closed positions. However, when left as the only connectionbetween front flap 200 and rear cover 300, inner and outer layers 102and 104 tend to bend in undesirable directions, causing front flap 200to misalign with rear cover 300 when in a closed position. Moreover, ifinner and outer layers 102 and 104 are overly stiff, front flap 200 canfail to lay flat against rear cover 300 when in a closed position.

To correct these issues, two rigid stiffeners 112 can be includedbetween inner layer 102 and outer layer 104 such that the accessory unit100 folds between the two rigid stiffeners 112 when placed in the closedposition. Rigid stiffeners 112 can be formed from any suitably rigidmaterial, including steel, aluminum, plastics, fabric scrims, and thelike. Rigid stiffeners 112 can be held in place by the same adhesivethat bonds inner and outer layers 102 and 104 together between rigidstiffeners 112 or any other suitable adhesive. In some embodiments,further flexibility can be added to the hinge system by performing a hotpress on inner and outer layers 102 and 104 in region 1202 between thetwo rigid stiffeners 112. In yet another embodiment, flexibility can befurther increased by reducing the thickness of inner and outer layers102 and 104 in region 1202 using an abrasion tool, laser, or splittingmachine prior to assembly. FIG. 12B shows another embodiment in whichrigid stiffeners 112 are replaced by magnets 1204. Magnets 1204 can beplaced with reversed polarities such that the magnets 1204 attract eachother when rotated into the closed position as shown by the arrow. Theaddition of magnets 1204 can further ensure that front flap 200 laysflat against the electronic device when placed in the closed position.

FIGS. 13A and 13B demonstrate multiple embodiments for allowing a userto access buttons on the electronic device through accessory unit 100without the need for a through hole. In FIG. 13A, electronic device 1302includes button 1304 that can be accessed by the user without removingelectronic device 1302. The shown portion of rear cover 300 includesinner layer 102, outer layer 104, and shell 118. Chamfered opening 1308can be created in shell 118 aligned with button 1304, and the spacecreated by chamfered opening 1308 can be filled with rigid filler 1306during the assembly process. Rigid filler 1306 can be formed from anysuitably rigid material, including aluminum, steel and plastic. When theuser depresses outer layer 104 above button 1304, the force istransferred through outer layer 104 to rigid filler 1306. Rigid filler1306 then transfers the force through inner layer 102 and depressesbutton 1304.

FIG. 13B demonstrates another embodiment providing access to button 1304on electronic device 1302. Similar to FIG. 13A, the shown portion ofrear cover 300 includes inner layer 102, outer layer 104, and shell 118.However, shell 118 contains through hole 1314 surrounded by blind hole1312, where blind hole 1312 is larger than through hole 1314. Thethinned section of shell 118 created by blind hole 1312 can be used as abonding area to over-mold outer button 1310. Outer button 1310 can beformed from any compression moldable material capable of forming abutton shape such as silicon. In other embodiments, a hard filler canalso be embedded in the over-molded material similar to the embodimentdescribed in FIG. 13A. When the user presses on outer layer 104, theforce is transferred through outer button 1310 and inner layer 102 todepress button 1304.

FIG. 13C shows a flow chart depicting process 1300 for creating a buttonassembly along the lines of FIG. 13A. In step 1302, a chamfered openingis created in a shell. The opening can be circular or any other feasibleshape. Preferably, the opening can have a shape roughly equal to that ofthe button on the electronic device that the button assembly isconfigured to depress. In step 1304, a rigid filler is placed within thechamfered opening. The rigid filler can have a chamfered edge as well,with the sides aligned to interlock with the chamfered opening in theshell. In steps 1306 and 1308, inner and outer layers are bonded to theshell. However, adhesives should not be placed between the inner andouter layers and the rigid filler, allowing the rigid filler to movefreely within the chamfered opening in the shell. Finally, in step 1310,the rigid filler can be aligned with a button on a correspondingelectronic device. When a force is applied to the outer layer, the forcecan be transferred through the rigid filler and depress the button theelectronic device.

FIG. 13D shows a flow chart depicting process 1350 for creating a buttonassembly along the lines of FIG. 13B. In step 1352, an opening iscreated in the shell. The opening can be circular or any other feasibleshape. Preferably, the opening can have a shape roughly equal to that ofthe button on the electronic device that the button assembly isconfigured to depress. In step 1354, the thickness of the shell in aregion surrounding the opening can be reduced. The thickness can bereduced through drilling, machining, or any other technically feasiblemeans. Furthermore, the material can be removed from the surface of theshell facing inwards towards the electronic device. Next, in step 1356,an outer button can be over-molded onto the area of reduced thicknesscreated in step 1354. The outer button can include a protruding portionthat can protrude through the opening in the shell and project outwardsfrom the electronic device. Finally, in steps 1358 and 1360, the innerand outer layers can be bonded to the shell. When a user depresses theappropriate region of the outer shell, the outer button transfers theresulting force through the inner layer and depresses the correspondingbutton on the electronic device.

FIGS. 14-16 illustrate an embodiment of an accessory unit 1400 accordingto the present disclosure. As illustrated, the accessory unit 1400 maycomprise a front flap 1500 and a rear cover 1600. The front flap qr00may include a plurality of segments 1501 a, 1501 b, 1501 c and a foldingregion 1504 positioned between each of the segments. The folding regions1504 may be configured to allow segments 1502 to fold with respect toeach other. The front flap 1500 may also include an end region 1506. Theend region 1506 pivotally couples the front flap 1500 to the rear cover1600.

In some embodiments, each of segments 1501 a, 1501 b, 1501 c can includeone or more inserts disposed therein. For example, segments 1501 a, 1501b, 1501 c can each include a pocket region where the inserts are placed,or alternatively, may be embedded within segments 1501 a, 1501 b, 1501 c(e.g., via insert molding). In embodiments using pockets, the pocketregions have a size and shape to accommodate corresponding inserts. Theinserts can have various shapes but are usually shaped to correspond tothe overall look of front flap 1500 (e.g., rectangular). The inserts canprovide structural support for front flap 1500. That is, the inserts canprovide stiffness to the cover assembly. Accordingly, the inserts may bereferred to as stiffeners. The inserts can be formed of rigid orsemi-rigid material adding resiliency to front flap 1500. Examples ofmaterials that can be used include plastics, fiber glass, carbon fibercomposites, metals, and the like. Some inserts can be formed ofresilient materials that further accommodate other components such asmagnetic elements. Magnetic elements can interact with a magnetic sensordisposed within an electronic device (not shown) associated withaccessory unit 1400. Magnetic elements also be arranged to form amagnetic attraction with an attractable magnetic element disposed withat least one insert. In some embodiment, attractable magnetic elementscan be formed of steel, or other ferromagnetic material, and take theshape of a thin sheet incorporated within an insert.

Front flap 1500 further includes folding regions 1504 that are thinnersegments 1501 a, 201 b, 201 c and do not include the inserts therebyallowing front flap 1500 to fold and make front flap 1500 easier tohandle. In one embodiment, segments 1501 b, and 1501 c can besubstantially wider than segment 1501 a in size. In this way, atriangular support structure having appropriate angles can be formed bypositioning segments 1501 a, 1501 b, 1501 c in a manner described inU.S. patent application entitled, “CONSUMER ELECTRONIC PRODUCT” byLauder et al. filed Dec. 17, 2010, having application Ser. No.12/971,536, now U.S. Pat. No. 8,344,836, which is incorporated herein byreference in its entirety.

One approach to forming at least one triangular support structure caninclude segment 201 a having a plurality of magnets and arranged to foldwith respect to segments 1501 b and 1501 c in such a way that at leastone magnetic element within segment 1501 a is magnetically attracted toa magnetically active element within segment 1501 c. In this way,segments 1501 a and segment 1501 c can be magnetically bound togetherforming a first triangular support structure. The triangular supportstructure can be used as a support structure for accessory unit 100.Accordingly, any electronic component supported by accessory unit 1400can also be supported. For example, when used as a support, anelectronic device having a display and supported by accessory unit 1400can be placed in such a way that visual content can be displayed atabout 75 degrees in relation to a horizontal surface below accessoryunit 1400. In another example, front flap 1500 can be folded to form asecond triangular support structure that can be used to position theelectronic device in an orientation suitable for using the electronicdevice as a keyboard. It should be noted, however, that these are onlyrepresentative examples of many other support structures that can beformed by front flap 1500.

While the flexible material of end region 1506 allows it to pivotallycouple front flap 200 to rear cover 1600, this may also causemisalignment between front flap 1500 and rear cover 1600 in a closedconfiguration. As shown in FIG. 16, a closed configuration refers tofront flap 1500 being substantially in contact with rear cover 1600. Toensure proper alignment between front flap 1500 and rear cover 1600 in aclosed configuration, some embodiments include end panels 1508 in endregion 1506. End panels 1508 may be configured to strengthen the endregion 206 such that the end region 1506 maintains alignment of outeredges 1510 a-c (collectively, “1510”) of the front flap 1500 withrespect to the lip portion 1604 of the rear cover 1600. End panels 1508could be made of fiberglass, steel, carbon fiber, plastic, orcombination thereof In some embodiments, end segments 1508 can have athickness that prevents them from showing through to a cosmetic surfaceof accessory unit 1400. In this way, end panels 208 can provide rigidityfor the pivotal coupling between front flap 1500 and rear cover 1600without affecting a cosmetic appearance of accessory unit 1400.

In FIG. 15, end region 1506 can include a material that is flexible andwhich thereby allows end region 1506 to bend. However, as a result ofemploying a flexible material in end region 1506, without end segments1608 front flap 1600 can tend to bend relative to the rear cover 1600 atend region 1506 in undesirable directions other than about a major axis1512 through end region 1506 under certain circumstances. In thisregard, end segments 208 can be configured to prevent misalignment ofouter edges 1510 of front flap 1500 with respect to lip portion 1604when the accessory unit is subjected to forces in directions other thanperpendicular to a major axis 1512 through the end region 1506.

Referring to FIG. 15, outer edges 1510 of front flap 1500 may contactlip portion 1604 when the front flap 1500 is in the closedconfiguration. Accordingly, front flap 1500 may define a substantiallylinear configuration when moved to the closed configuration. In thisregard, end segments 1508 can be substantially coplanar with the othersegments 1501 a, 1501 b, 1501 c and the folding regions 1504 of thefront flap 1500 when the front flap 1500 is in the closed (or folded)configuration. However, a portion of end region 1506 adjacent the endsegments 1508 bends to enable the end region 1506 to function as ahinge, as noted above.

In some embodiments, as illustrated in FIG. 15, lip portion 1604 mayextend outwardly beyond the outer edges 1510 of front flap 1500. In thisregard, lip portion 1604 may function to protect a consumer electronicdevice received in the chamber 1610 (referred to in FIG. 16) in rearcover 1600 from damage to the edges of the consumer electronic devicewhen dropped or otherwise subjected to impact. However, in otherembodiments, the outer edges 1510 of the front flap 1500 and the lipportion 1604 may extend to the same dimensions, or the outer edges 1510of the front flap 1500 may extend beyond the lip portion 1604. When usedas a structural element, lip portion 1604 includes material havingmechanical properties sufficient to retain the consumer electronicdevice within chamber 1610 of rear cover 1600. Moreover, in addition tothe ability to retain the consumer electronic product within chamber1610, lip portion 1604 also retains enough flexibility to allow theconsumer electronic device to be inserted and removed from chamber 1610numerous times without undue exertion by an end-user, a potentiallydamaged accessory unit 1400, or the consumer electronic device.

The material(s) defining the accessory unit 1500 may vary. In oneembodiment, the entire accessory unit 1500 may be formed from a singlematerial. However, as noted above, in other embodiments, it may bedesirable to form the accessory unit 1500 from multiple materials totake advantage of differing material properties.

As shown in FIG. 15, accessory unit 1400 may further include one or moremagnetic elements 1408 in front flap 1600. For example, magneticelements 1408 disposed within segment 201 a can be configured tointeract with an attachment feature of a consumer electronic devicepositioned within rear cover 1600. Magnetic elements 1408 can bemagnetically attracted to the attachment feature of the consumerelectronic device when accessory unit 1400 is in a closed configurationsuch that the front flap 1500 is releasably retained in thisconfiguration. The front flap 1500 may further include a magneticelement 1410 configured to interact with a magnetically sensitivecircuit embedded in the consumer electronic device configured to detectthe presence, absence, or change from presence to absence, or viceversa, of the magnetic element 1410. For example, the magneticallysensitive circuit may include a Hall Effect sensor.

Magnetic elements 1408 and 1410 of accessory unit 1400 can be configuredto provide various other types of functionality. For example, the HallEffect sensor can respond to the presence (or absence) of the magneticfield by generating a signal. The signal can be used to alter anoperating state of the consumer electronic device. Magnetic element 1410can be positioned on front flap 200 in a location that triggers the HallEffect sensor to generate the signal when the cover is placed on or inproximity to a surface of the consumer electronic device. The signal canindicate that the front flap 200 is in a predetermined position relativeto the consumer electronic device that can result in a change in anoperating state of the consumer electronic device. The signal can alsobe used to alter the operating state to a state having functionalitysuitable for the consumer electronic device being fully covered.

In situations where the consumer electronic device includes a display,the functioning of the consumer electronic product can be altered insuch a way that the display is prevented from displaying visual content.On the other hand, when the portion of front flap 1500 having magneticelement 1410 is removed to the point where the Hall Effect sensor nolonger senses the magnetic field of magnetic element 1410, then the HallEffect sensor can generate another signal. This other signal can resultin the consumer electronic device entering a different operating stateconsistent with at least a portion of the display being uncovered andviewable. In this state, the functionality of the tablet computer can bealtered such that the display is enabled to present visual content. Itshould be noted that the above described attachment feature, and themagnetically sensitive circuit are discussed in U.S. Patent Applicationentitled, “CONSUMER ELECTRONIC PRODUCT” by Lauder et al. filed Dec. 17,2010 having application Ser. No. 12/971,536, now U.S. Pat. No.8,344,836, which is incorporated herein by reference in its entirety.

FIG. 16 shows accessory unit 1400 in a closed configuration. Further, inother embodiments, rear cover 1600 could be made with an adhesivelyformed base material, or alternative, rear cover could simply be aninner layer adhesively attached to an outer layer. In the embodimentshown in FIG. 2B, rear cover 1600 includes shell 118. Shell 1418 may beformed by a thermoforming process using plastic, compression molding,injection molding, or a combination thereof Shell 1418 could be madefrom any rigid material known in the art for making a case for anelectronic housing device. In addition to shell 1418, rear cover 1600includes inner layer 1402 is attached to an inner surface of shell 1418,and outer layer 1404 is also attached to shell 1418. As shown FIG. 16,inner layer 1402 and outer layer 1404 generally terminate at one endnear lip portion 1604 of rear cover. Inner layer 1402 and outer layer1404 extend through rear cover 1600 to define an outer periphery offront flap 1600. Inner layer 1402 and outer layer 1404 generallyterminate at another end near reinforcement element 1416. In someembodiment, reinforcement element 116 can be formed from a relativelyrigid material such as plastic, steel, carbon fiber, fiberglass, etc. Inthe embodiment shown in FIG. 16, reinforcement element 1416 includes anadhesive disposed between inner layer 1402 and outer layer 1404.

FIGS. 17A-17G show a process for forming rear cover portion of anaccessory unit. For simplicity, this set of figures omits front flap1500. FIGS. 17A-17C show various embodiments of shell 1700. In FIG. 3A,a thermoformed plastic shell 1700 made of a single material is depicted.A recessed portion 1702 of shell 1700 can have a substantially uniformthickness, while a lip portion 1704 can be integrally formed withrecessed portion 1702. Lip portion 1704 can be injection molded on torecessed portion 1702, thereby removing any need for a subsequentbonding operation. In another embodiment shown in FIG. 17B, plasticrecessed portion 1702 is compression molded to a lip portion 1706. Insome embodiments, lip portion 1706 is made from reinforced glass fiber.Lip portion 1706 can be constructed by overlaying a number ofunidirectional glass fibers in a continuous loop and then forming themin accordance with a geometry of lip portion 1706. In FIG. 17C, lipportion 1706 also includes a substantial portion of sidewalls andaccordingly, forms a substantial portion of the recessed portion ofshell 1700. Portions of a shell 1700 that include reinforced material(such as reinforced glass fiber) can substantially add to an overallstiffness of shell 1700.

FIG. 17D shows a first assembly step, which depicts shell 1700 asdepicted in FIG. 17A and a first layer 1710 (which may also be referredto as an inner layer). In some embodiments, shell 1700 can be athermoformed plastic shell, a compression molded shell, an injectionmolded shell, or a combination thereof In some embodiments, first layer1710 is a microfiber layer; microfiber layer could further be apreformed microfiber layer. It should be understood that the embodimentsshown in FIGS. 17B and 17C could also be used in the assembly stepsshown in FIGS. 17D-17G. First layer 1710 can be a preformed microfiberlayer. First layer 1710 can be adhesively coupled to a central portion1709 of recessed portion 1802. In one embodiment, first layer 1710 canbe adhesively coupled to shell 1700 by a thermoplastic adhesive, whilein other embodiments a thermosetting adhesive can be utilized. In bothcases, shell 1700 and first layer 1710 can be heated to activate thethermal adhesive. FIG. 17E shows a second step in which an expandingdevice is used to press peripheral portions 1711 of first layer 1710around a lip portion 1704 of shell 1700, thereby adhesively engaging theperipheral portions of first layer 1710 about lip portion 1704 and alongsidewalls of shell 1700. Because first layer 1710 is preformed toconform with an inside surface of shell 1700, undue stretching of firstlayer 1710 can be controlled and avoided. In this way, pin holes can beprevented from forming in first layer 1710, thereby preventing adhesiveand/or a portion of shell 1700 from showing through first layer 1710.

In FIG. 17F, once first layer 1710 is in adhesive contact with shell1700 and while an expanding device (not shown) keeps the first layer1710 under tension, an exposed portion of shell 1700 can be cooled at acontrolled rate to establish desired characteristics in an adhesivecoupling between first layer 1710 and shell 1700. For example, in someembodiments, cooling can be varied to provide varying stiffness acrossrecessed portion 1702 and/or lip portion 1704. In FIG. 17G, second layer1712 (also referred to as an outer layer) can be adhesively coupled toan exposed portion of shell 1700. Second layer 1712 could be made ofleather. In one embodiment, the adhesive coupling can be accomplishedusing a concave fixture to press second layer 1712 against shell 1700.First end 1713 and second end 1714 of second layer 1712 can be coupledto first end 1716 and second end 1717, respectively, of first layer1710. First layer 1710 and second layer 1712 can come together to form asubstantially zero flange design. The phrase “zero flange design” refersto a bonded region of first layer 1710 and second layer 1712 that freeof outward protrusion (with respect to shell 1700) of first layer 1710or second layer 1712. In other words, the region where first layer 1710is bonded to second layer 1712 extends from shell 1700 a distanceapproximately similar to a thickness (width) of first layer 1710 orsecond layer 1712). The zero flange design further maintains the bondedrelationship between first layer 1710 and second layer 1712. An exampleof zero flange design is shown where second end 1714 of second layer1712 bonds with first layer 1710. In some embodiments, a slight flangecan be formed to increase surface area between the two layers, therebyimproving adhesion. It should be noted that ideal fit and finish of anaccessory unit is accomplished by tuning an amount of stretch in bothfirst layer 1710 and second layer 1712. Also, the adhesive may be curedby, for example, radiation (from a light source such as ultraviolet (UV)light) and/or a time lapse sufficient for the adhesive to bond firstlayer 1710 and second layer 1712 to shell 1700. Other cooling means arefurther discussed below.

FIG. 18A shows a cross sectional view of a sidewall of rear cover 1600having an electronic device 1800 disposed therein. This view shows howlip portion 1604 can act via interference fit to retain consumerelectronic device 1800 in chamber 1610. When electronic device 1900 isinserted into rear cover 1600, lip portion 304 extends outward in adirection away from electronic device 1900, then retracts to theoriginal (resting) position once the electronic device 1900 is fullyreceived by the rear cover 1600. The interference fit can cause anelectronic device 1900 to snap into place within an accessory unit dueto a geometry of lip portion 1604 not conforming precisely to an outersurface of consumer electronic device 1800. In other words, thecurvature of rear cover 1600 may not completely correspond to thecurvature of electronic device 1900. FIG. 18A further illustrates aclose-up showing relationship between lip portion 1604 and chamferedportion 1804 of electronic device 1800. Here, engaging region 1815 ofthe inner layer 1402 contacts electronic device 1800. However, edge 1605of lip portion 1604 is angled such that inner layer 1402 does notcontact electronic device 1800. The area is shown as disengaging region1816. Such a configuration contributes to the snap effect duringinserting and extracting electronic device 1800 from an accessory unit.It should be understood this relationship between extends around theperimeter of the lip portion 1604 and electronic device 1900.

This feature allows a user to have affirmative confirmation (forexample, by hearing a “snap”) that consumer electronic device 1800 issecured within an accessory unit, or when electronic device 1800 isreleased/removed from an accessory unit. Also, lip portion 1604 canavoid contacting display cover glass 1802. This allows all of displaycover glass 1802 to remain visible, which may be desirable inembodiments in which electronic device 1800 includes a display thatextends near the edges of the top surface of electronic device 1800.

In particular, the curvature of rear cover 1600 may not completelycorrespond to the curvature of electronic device. For example, FIG. 18Aillustrates a close-up of the relationship between lip portion 304 andchamfered portion 1804 of electronic device 1800. Here, engaging region1915 of the inner layer 1402 contacts electronic device 1800. However, alower section of lip portion 1604 is angled such that inner layer 1402does not contact electronic device 1800. The area is shown asdisengaging region 1816. Such a configuration contributes to the snapeffect of inserting and extracting electronic device 1800 from anaccessory unit. It should be understood this relationship betweenextends around the perimeter of the lip portion 304 and electronicdevice 1800.

FIG. 18B shows a cross sectional view of a sidewall of rear cover 1600that includes embossed portion 1714 b. A tactile feel of embossedportion 1714 b can be enhanced by adding a filling member 1806 suspendedbetween inner layer 1402 and outer layer 1404. Filling member 1806 couldinclude a plastic member other or a more flexible member such assilicone. In the embodiment shown in FIG. 18B, embossed portion 1714 bcan correspond to a volume control of an electronic device. A portion ofshell 1418 has been removed to allow user interaction with the volumecontrol. In this way filling member 1806 can provide a strong tactilefeeling to a user manipulating the volume control. Inner layer 1402 andouter layer 1404 can cause filling member 1806 to hover in position andprovide resistance in response to a user actuation. In some embodiments,filling member 1806 can be surrounded by low durometer rubber during aninsert molding operation to provide additional spring/flexibility foractuation of the volume control. In other embodiments, additionaltactile enhancements can be made. For example, a portion of outer layer104 that engages filling member 1806 can be made thinner so that thereis less compressible material (e.g, less outer layer 1404) when a useractuates the volume control. A treatment can be applied to the leatherlayer to adjust a hardness of the leather layer above filling member1806. A skiving method (discussed below) could also be used to remove aportion of outer layer 1404.

FIG. 18C shows a cross sectional side view of a sidewall or rear cover1600 that includes an aperture 1612 f for coupling a data cable to dataport 1808 of electronic device 1800 disposed within an accessory unit.Depending on the electronic device, aperture 1612 f could receive othermembers known in the art for coupling to an electronic device through anaperture of an accessory unit. Aperture 1612 f can have sidewalls 1810that extend normal from an outside surface of electronic device 1800.When compared with an aperture cut in a direction substantially parallelto a top surface of electronic device 1800, aperture 1612 f avoids sharpangles jutting out and having a higher potential of fraying or eveninterfering with use of data port 1808. Rather, aperture 1812 f, asshown in FIG. 18C, is cut such that the circular wall is normal to thesurface of electronic device 1800. This design leaves edges of aperture1612 f less vulnerable to contact from external objects. While such anopening would normally require a three dimensional cutting path to betraced, a tapered cutter can be utilized to cut aperture 1612 f asdepicted without complexities associated with a three dimensionalcutting path. FIG. 18D shows another configuration of aperture 1612 f.In this embodiment, a debossed aperture 1612 f is depicted. Here, shell1418 is made thinner near aperture 1612 f to provide an appearance of anaccessory unit having a narrower width. In some embodiments, shell 1418can end prior to aperture 1612 f such that only inner layer and outerlayers remain at the edge of aperture 1612 f. In other embodiments,inner layer 1402 can made thinner and/or end prior to aperture 1612 f.

It should be understood that the depicted techniques can be applied toany of apertures 312 as depicted in FIG. 1A. In contrast, apertures 312e (configured to audio from an electronic device to pass throughaccessory unit 100) can be formed using a different process. In oneembodiment, apertures 312 e can be drilled by a spindle head rotating at80,000 rpm to create a substantially clean hole through rear cover 300.In other embodiments, a spiral shaped cutter can be used to formapertures 312 e. The spiral shaped cutter can push chips towards acenter portion of apertures 312 e, thereby forming a clean cut.

FIGS. 19A-19E shows a series of illustrations describing a skivingmethod. Skiving can be applied by a skiving machine, to changecharacteristics of a fabric layer, and more specifically to change amaterial thickness of the fabric. A leather portion of front flap 200may be too rigid along folding regions 204 (shown in FIGS. 1A-2A) forcertain applications. This excessive rigidness may prohibit front flap200 from easily folding to form a support structure. The skiving methodoffers a reliable method for removing material from front flap 200 tocreate, for example, folding regions 204.

FIG. 19A shows a template 1902 configured to establish a skivingpattern. In some embodiments template 1902 can be made of plastic andcan includes protrusions 1904, 1906 that determine where material is tobe removed. Although protrusions 1904, 1906 are depicted as beingsubstantially the same size and shape, other sizes and shapes arepossible and can serve different purposes. In other embodiments, therecould be at least three protrusions. In FIG. 19B, leather layer 1908 islaid across template 1902, with the cosmetic side 1909 contactingtemplate 1902. By laying the cosmetic side 1909 against template 1902,subsequent cutting operations do not substantially affect an exteriorfinish of leather layer 1908. In FIG. 19C a cutting operation isperformed along cutting line 1910. The cutting operation can beperformed by a thin slicing blade that cuts parallel to a top surface oftemplate 1902. FIG. 19D shows leather layer 1908 after the cuttingoperation. Because protrusions 1904, 1906 cause leather layer to curvegradually, a resulting thickness of leather layer 1908 also variesgradually (corresponding to protrusions 1904, 1906) to provide a smooththickness transition. Finally, FIG. 19E shows leather layer 1908 removedfrom template 1902. It should be noted that in addition to increasingflexibility in folding regions 204, this skiving method can be used toprovide space to embed various items beneath leather layer 1908. Forexample, flexible circuits, wiring, and even magnetic elements could bepartially or completely hidden by such a technique.

FIG. 20 shows a block diagram illustrating a method for assembling anaccessory unit. In a first step 2002, a shell and front flap segmentinserts are provided. In one embodiment the shell can be a thin walledthermoformed plastic shell and the segment inserts can be glass fiber.In other embodiments, the shell can be formed by compression molding, ora combination of thermoforming and compression molding. In step 2004,the shell and front flap segment inserts can be positioned between anouter layer and an inner layer. Segment inserts may include magneticelements, filling elements (such as a plastic piece or silicone), or acombination thereof. In some embodiments, magnetic elements are formedinside the segments inserts, and accordingly, are disposed between theinner layer and the outer layer in conjunction with the segment inserts.

In step 2006, the outer layer and inner layer are adhesively coupledtogether around both the shell and the front flap segments. In someembodiments, a complex press can be utilized that seals the outer layerand inner layer around the shell and front flap in a single bonding (orlaminating) operation. In other embodiments, the microfiber layer isfirst adhesively bonded to an inside surface of the shell. The adhesivebond can be established by a thermoplastic or thermosetting adhesive.One advantage of a thermosetting adhesive is that lower settingtemperatures can be used and an applicator can be utilized to spread theadhesive at varying thicknesses thereby generating regions of greaterand lesser rigidity. In addition, the leather layer is not subject tohigher heat that is required to activate other adhesives.

Subsequent to bonding the microfiber layer to a bottom portion of theshell, a spreading element can be utilized to adhere peripheral portionsto sidewalls of the shell, including a top side of a lip portion of theshell as well as the sidewalls of the shell. After the microfiber ispressed against the shell the shell, the shell can be cooled to causethe adhesive to properly set. Cooling means may include running coolantthrough the tool (spreading element), cooling the tool (which extractsheat from the microfiber/shell configuration), using air jets in thetool to push air onto the microfiber/shell configuration, switching outthe heated tool with a cool tool, or a combination thereof Next, theleather layer is adhered to an opposite side of the shell. Subsequently,the leather layer and microfiber seal around the front flap segmentinserts and various other internal components of the accessory unit. Instep 2008, a machining operation can be applied to form apertures andembossments along a surface of the accessory unit to provide easy accessto controls on a compatible consumer electronic product.

FIGS. 21A-21D show various alternative hybrid shell embodiments. Thehybrid shell embodiments each include a shell formed by compressionmolding at least two different materials together. In this way differentcharacteristics can be provided to different portions of the shell. Eachof the following embodiments can be formed during a single compressionmolding operation. In FIG. 21A shell 2100 is made from substantiallystiff material such as glass fiber or a carbon fiber weave. Portions2102 and 2104 can correspond to an input/output openings that can beareas of high strain. In this way the potential strain on the cover canbe ameliorated. In FIG. 21B shell 2110 is made from substantiallyflexible material, such as a thermoplastic. Regions 2112 and 2114 cancorrespond to edge areas to firm up a feel of the edge portions of theaccessory unit. In some embodiments this can prevent the accessory unitfrom having a floppy edge feel. In other words, the accessory unit feelsrigid and robust when held by a user. In FIG. 21C, shell 2120 is madefrom a substantially flexible material and having an embedded attractionplate 2122 made from a magnetically attractable material such as steel.By embedding attraction the plate 2122 within shell 2120, magneticelements within the front flap can attract to the attraction plate 2122,such that the front flap is secured to the shell 2120 during, forexample, use of an electronic device. FIG. 21D shows a shell 2130 havinga stiff outer periphery 2132 that can be formed from, for example, glassfiber. Outer periphery 2132 can include both a lip portion of shell 830and at least sidewalls of shell 830, such that a protected electronicdevice is firmly seated within the accessory unit. The shells describedin FIGS. 21A-D may include an outer layer (such as leather) disposed onan outer surface of the shell. It should be understood that the outerlayer is sufficiently thin and/or the magnetic attraction issufficiently strong such that front flap attracts to shell.

Indicia, such as a logo or symbol, may be disposed on the front flapand/or the rear cover. Indicia can be formed by removing a portion of asurface of the leather layer corresponding to a shape of the logo.Unfortunately, the consistency or uniformity of an underlying layer ofleather can vary in accordance with a grain or other individualcharacteristic of the leather. To compensation, in some embodiments, theunderlying layer can be treated with water or steam to provide aparticular color for the indicia. Variations in temperature, time and/oroperating pressure can affect the color or colors obtained. To furthercreate indicia with a more uniform appearance, a dye or ink can beapplied to the indicia.

FIG. 22 is a block diagram of an arrangement 2200 of functional modulesutilized by an electronic device. The electronic device can, forexample, be a tablet computer. The arrangement 2200 includes anelectronic device 2202 that is able to output media for a user of theportable media device but also store and retrieve data with respect todata storage 2204. The arrangement 2200 also includes a graphical userinterface (GUI) manager 2206. The GUI manager 2206 operates to controlinformation being provided to and displayed on a display device. Thearrangement 2200 also includes a communication module 2208 thatfacilitates communication between the portable media device and anaccessory device. Still further, the arrangement 2200 includes anaccessory manager 2210 that operates to authenticate and acquire datafrom an accessory device that can be coupled to the portable mediadevice.

FIG. 23 is a block diagram of an electronic device 2350 suitable for usewith the described embodiments. The electronic device 2350 illustratescircuitry of a representative computing device. The electronic device2350 includes a processor 2352 that pertains to a microprocessor orcontroller for controlling the overall operation of the electronicdevice 2350. The electronic device 2350 stores media data pertaining tomedia items in a file system 2354 and a cache 2356. The file system 2354is, typically, a storage disk or a plurality of disks. The file system2354 typically provides high capacity storage capability for theelectronic device 2350. However, since the access time to the filesystem 2354 is relatively slow, the electronic device 2350 can alsoinclude a cache 2356. The cache 2356 is, for example, Random-AccessMemory (RAM) provided by semiconductor memory. The relative access timeto the cache 2356 is substantially shorter than for the file system2354. However, the cache 2356 does not have the large storage capacityof the file system 2354. Further, the file system 2354, when active,consumes more power than does the cache 2356. The power consumption isoften a concern when the electronic device 2350 is a portable mediadevice that is powered by a battery 2374. The electronic device 2350 canalso include a RAM 2370 and a Read-Only Memory (ROM) 2372. The ROM 2372can store programs, utilities or processes to be executed in anon-volatile manner. The RAM 2370 provides volatile data storage, suchas for the cache 2356.

The electronic device 2350 also includes a user input device 2358 thatallows a user of the electronic device 1350 to interact with theelectronic device 2350. For example, the user input device 1558 can takea variety of forms, such as a button, keypad, dial, touch screen, audioinput interface, visual/image capture input interface, input in the formof sensor data, etc. Still further, the electronic device 2350 includesa display 2360 (screen display) that can be controlled by the processor2352 to display information to the user. A data bus 2366 can facilitatedata transfer between at least the file system 2354, the cache 2356, theprocessor 2352, and the CODEC 2363.

In one embodiment, the electronic device 2350 serves to store aplurality of media items (e.g., songs, podcasts, etc.) in the filesystem 2354. When a user desires to have the electronic device play aparticular media item, a list of available media items is displayed onthe display 1560. Then, using the user input device 2358, a user canselect one of the available media items. The processor 2352, uponreceiving a selection of a particular media item, supplies the mediadata (e.g., audio file) for the particular media item to a coder/decoder(CODEC) 2363. The CODEC 1563 then produces analog output signals for aspeaker 2364. The speaker 2364 can be a speaker internal to theelectronic device 2350 or external to the electronic device 2350. Forexample, headphones or earphones that connect to the electronic device2350 would be considered an external speaker.

The electronic device 2350 also includes a network/bus interface 2361that couples to a data link 2362. The data link 2362 allows theelectronic device 2350 to couple to a host computer or to accessorydevices. The data link 2362 can be provided over a wired connection or awireless connection. In the case of a wireless connection, thenetwork/bus interface 2361 can include a wireless transceiver. The mediaitems (media assets) can pertain to one or more different types of mediacontent. In one embodiment, the media items are audio tracks (e.g.,songs, audio books, and podcasts). In another embodiment, the mediaitems are images (e.g., photos). However, in other embodiments, themedia items can be any combination of audio, graphical or visualcontent. Sensor 2376 can take the form of circuitry for detecting anynumber of stimuli. For example, sensor 2376 can include a Hall Effectsensor responsive to external magnetic field, an audio sensor, a lightsensor such as a photometer, and so on.

The various aspects, embodiments, implementations or features of thedescribed embodiments can be used separately or in any combination.Various aspects of the described embodiments can be implemented bysoftware, hardware or a combination of hardware and software. Thedescribed embodiments can also be embodied as computer readable code ona computer readable medium for controlling manufacturing operations oras computer readable code on a computer readable medium for controllinga manufacturing line. The computer readable medium is any data storagedevice that can store data which can thereafter be read by a computersystem. Examples of the computer readable medium include read-onlymemory, random-access memory, CD-ROMs, HDDs, DVDs, magnetic tape, andoptical data storage devices. The computer readable medium can also bedistributed over network-coupled computer systems so that the computerreadable code is stored and executed in a distributed fashion.

The foregoing description, for purposes of explanation, used specificnomenclature to provide a thorough understanding of the describedembodiments. However, it will be apparent to one skilled in the art thatthe specific details are not required in order to practice the describedembodiments. Thus, the foregoing descriptions of the specificembodiments described herein are presented for purposes of illustrationand description. They are not targeted to be exhaustive or to limit theembodiments to the precise forms disclosed. It will be apparent to oneof ordinary skill in the art that many modifications and variations arepossible in view of the above teachings.

1. An accessory unit, comprising: a front flap comprising: a pluralityof segments; an inner layer and an outer layer disposed on either sideof the plurality of segments, wherein the inner and outer layers allowthe front flap to fold in regions between the plurality of segments; andan end region; a rear cover coupled to the front flap, the rear covercomprising: a shell forming a recessed region, wherein the inner layerand the outer layer bonded on either side of the shell; a chamferedopening in the shell; a rigid filler disposed within the chamferedopening and in contact with the inner layer and the outer layer, whereinthe rigid filler is configured to transfer a force exerted on the outerlayer to a button disposed on the electronic device; and a lipmechanically coupled along a periphery of the shell, wherein the lip isformed from a material more rigid than the shell and is configured toretain an electronic device within the recessed region of the shell;wherein the end region of the front flap hingedly couples the front flapto the rear cover and the front flap is configurable between a closedconfiguration in which the front flap at least partially covers theopening to the recessed region and an open configuration in which theopening to the recessed region is at least partially uncovered.
 2. Theaccessory unit as recited in claim 1, wherein the end segment furthercomprises two rigid stiffeners spanning the length of the end segment.3. The accessory unit as recited in claim 2, wherein the rigidstiffeners are made of steel.
 4. The accessory unit as recited in claim2, the rigid stiffeners further comprising magnets, wherein the magnetsare oriented such that the magnets attract each other when the accessoryunit is placed in a closed position.
 5. The accessory unit as recited inclaim 1, wherein the lip is formed integrally with the shell.
 6. Theaccessory unit as recited claim 1, wherein the lip is molded onto theshell during a curing process for the shell.
 7. The accessory unit asrecited in claim 6, further comprising a unidirectional fiber includedwithin the lip and spanning a periphery of the lip.
 8. The accessoryunit as recited in claim 7, wherein the unidirectional fiber comprisesKevlar.
 9. The accessory unit as recited in claim 1, wherein the rearcover includes an opening configured to align with a camera included inthe electronic device.
 10. The accessory unit as recited in claim 9,wherein the thickness of the shell is reduced in a region surroundingthe opening configured to align with the camera so as to reduce aportion of the shell that is visible to a user.
 11. The accessory unitas recited in claim 1, wherein the inner layer and the outer layerfurther comprise a microfiber material.
 12. (canceled)
 13. The accessoryunit as recited in claim 1, further comprising: an opening in the shell;a region of reduced thickness in the shell surrounding the opening inthe shell; and an outer button over-molded onto the region of reducedthickness in the shell and protruding through the opening in the shell,wherein the outer button is disposed between the inner layer and theouter layer; wherein the outer button is configured to transfer a forcedexerted on the outer layer to a button disposed on the electronicdevice. 14.-18. (canceled)
 19. A method for forming a button assembly onan accessory unit, the accessory unit comprising a structural shell, aninner cosmetic layer, and an outer cosmetic layer, the methodcomprising: creating a chamfered opening in the structural shell,wherein the chamfered opening is aligned with a button on an electronicdevice configured to rest within the accessory unit; positioning a rigidfiller within the chamfered opening, wherein the rigid filler has achamfered edge corresponding to the chamfered opening in the structuralshell; and bonding the inner cosmetic layer and outer cosmetic layer oneither side of the structural shell, wherein no adhesive is allowed tocontact the rigid filler; wherein the rigid filler is configured totransfer a force exerted on the outer layer to a button disposed on theelectronic device.
 20. The method as recited in claim 19, wherein therigid filler is made from plastic.
 21. The method as recited in claim19, wherein the rigid filler is smaller than the chamfered opening. 22.A button assembly for depressing a button on an electronic devicethrough an accessory having a structural shell, an inner cosmetic layerbonded to the structural shell, an outer cosmetic layer bonded to thestructural shell, the button assembly comprising: an opening in thestructural shell; a region of reduced thickness in the structural shellsurrounding the opening in the structural shell; and an outer buttonover-molded onto the region of reduced thickness in the structural shelland protruding through the opening in the shell, wherein: the outerbutton is disposed between the inner cosmetic layer and the outercosmetic layer, the outer button is configured to transfer a forcedexerted on the outer cosmetic layer to a button disposed on theelectronic device.
 23. The button assembly as recited in claim 22,wherein the outer button comprises silicon.
 24. The button assembly asrecited in claim 23, wherein the outer button further comprises a rigidfiller.
 25. The button assembly as recited in claim 24, wherein therigid filler is made from plastic. 26.-45. (canceled)